Back to EveryPatent.com
| United States Patent |
6,177,163
|
|
Blok
, et al.
|
January 23, 2001
|
Markable repositionable adhesive sheet dispensing roll for use in an
industrial setting
Abstract
Adhesive sheet assemblies are described comprising a continuous carrier in
roll form, a series of longitudinally spaced adhesive sheets on the
carrier, and at least one cut in the web defining, for each adhesive
sheet, one cover piece cut from the carrier such that the cover piece has
an outer peripheral edge within the first portion on the backside of the
adhesive sheet, so that the cover piece may be separated from the web and
retained on the first portion of the backside of the adhesive sheet when
the adhesive sheet is peeled off the carrier due to adhesion between the
cover piece and the adhesive sheet. Preferably, at least 40 percent of the
total length of the outer peripheral edge of each cover piece is
substantially in registration with the outer peripheral edge of the
adhesive sheet to which it is adhered. Each adhesive sheet comprises a
flexible polymer film, polymer-reinforced sheet or cloth and is capable of
being removed from a substrate to which it is adhered without leaving an
adhesive residue on the substrate. Kits for dispensing the adhesive sheet
assembly, processes for making the adhesive sheet assembly and processes
for printing the same are also described.
| Inventors:
|
Blok; Lana M. (Bayside, WI);
Wenzler; Larry E. (Oak Creek, WI);
Wright; Gene A. (Pewaukee, WI)
|
| Assignee:
|
Tricor Direct, Inc. (Branford, CT)
|
| Appl. No.:
|
102337 |
| Filed:
|
June 22, 1998 |
| Current U.S. Class: |
428/40.1; 156/268; 156/269; 156/271; 156/277; 428/41.3; 428/41.7; 428/41.8; 428/42.2; 428/42.3; 428/906; 428/914 |
| Intern'l Class: |
B32B 009/00; B32B 031/00 |
| Field of Search: |
428/40.1,41.3,41.7,41.8,47,906,914,43,42.3,42.2,44,77,78
156/250,269,268,271,522,277
|
References Cited
U.S. Patent Documents
| 1965289 | Jul., 1934 | Humphner | 41/33.
|
| 2278673 | Apr., 1942 | Savada et al. | 154/43.
|
| 3885070 | May., 1975 | Chapman | 428/42.
|
| 4032679 | Jun., 1977 | Aoyagi | 428/42.
|
| 4055249 | Oct., 1977 | Kojima | 206/447.
|
| 4060168 | Nov., 1977 | Romagnoli | 206/216.
|
| 4188250 | Feb., 1980 | Grass | 156/253.
|
| 4317852 | Mar., 1982 | Ogden | 428/40.
|
| 4584219 | Apr., 1986 | Baartmans | 428/42.
|
| 4968540 | Nov., 1990 | Linsenbigler | 428/5.
|
| 5182152 | Jan., 1993 | Ericson | 428/42.
|
| 5220858 | Jun., 1993 | Allen et al. | 83/880.
|
| 5225260 | Jul., 1993 | McNaul et al. | 428/40.
|
| 5262216 | Nov., 1993 | Popat et al. | 428/42.
|
| 5279875 | Jan., 1994 | Juszak et al. | 428/42.
|
| 5484168 | Jan., 1996 | Chigot | 283/67.
|
| 5512343 | Apr., 1996 | Shaw | 428/40.
|
| 5601313 | Feb., 1997 | Konkol et al. | 283/81.
|
| 5686159 | Nov., 1997 | Langan | 428/40.
|
| 5704648 | Jan., 1998 | Brown et al. | 283/81.
|
| 5827591 | Oct., 1998 | Blok et al. | 428/41.
|
| 5882753 | Mar., 1999 | Pedginski et al. | 428/40.
|
| 5935670 | Aug., 1999 | Downs | 428/40.
|
| Foreign Patent Documents |
| 0 431 825 A2 | Jun., 1991 | EP.
| |
Primary Examiner: Ahmad; Nasser
Assistant Examiner: Jessen; Derek
Attorney, Agent or Firm: Whyte Hirschboeck Dudek SC
Claims
What is claimed is:
1. An adhesive sheet assembly comprising:
a continuous carrier of flexible sheet material in roll form, the carrier
having two substantially parallel side edges extending in a longitudinal
direction of the carrier;
a series of longitudinally spaced adhesive sheets on the carrier, each
adhesive sheet having a front side facing away from the carrier capable of
receiving markings, a back side facing toward the carrier substantially
covered with a pressure sensitive adhesive, the back side having a first
portion and a second portion;
a continuous cut in the carrier defining, for each adhesive sheet, one
cover piece cut from the carrier such that the cover piece has an outer
peripheral edge within the first portion on the backside of the adhesive
sheet, so that the cover piece may be separated from the carrier and
retained on the first portion of the backside of the adhesive sheet
without extending beyond the outer peripheral edge of the adhesive sheet
when the adhesive sheet is peeled off the carrier due to adhesion between
the cover piece and the adhesive sheet,
wherein
at least 40 percent of the total length of the outer peripheral edge of
each cover piece is substantially in registration with the outer
peripheral edge of the adhesive sheet to which it is adhered;
the continuous cut does not extend through the substantially parallel side
edges of the continuous carrier; and
each longitudinally spaced adhesive sheet on the carrier is not perforated
or cut parallel to the outer peripheral edge of the cover piece adhered to
that adhesive sheet; or
each adhesive sheet comprises a flexible polymer film, polymer-reinforced
sheet or cloth having a Taber stiffness of not less than 0.03 measured
according to ASTM D747 A;
the pressure sensitive adhesive has an initial tack value of at least 200 g
measured according to ASTM D2979 on a Polyken.TM. probe tack tester, an
adhesive tack sufficient to prevent conformability failure of the adhesive
sheet after 10 hours conformability testing, and an adhesive strength of
at least 100 N/m according to ASTM D1000; and
each adhesive sheet is capable of being removed from a substrate to which
it is adhered without leaving a substantial amount of residue on the
substrate.
2. The assembly of claim 1, wherein the film, sheet or cloth has a tensile
strength of at least 2000 N/m and a minimum elongation of 4 percent, each
measured according to ASTM D1000.
3. The assembly of claim 1, wherein the film, sheet or cloth has a tensile
strength of at least 5000 N/m and a minimum elongation of at least 50
percent, each measured according to ASTM D1000.
4. The assembly of claim 1, wherein the adhesive comprises an acrylic-based
polymer.
5. The assembly of claim 1, wherein the adhesive comprises an elastomer and
a tackifier.
6. The assembly of claim 5, wherein the elastomer is a natural rubber, an
elastomeric block copolymer or polyisobutylene elastomer, or a combination
of two or more thereof.
7. The assembly of claim 6, wherein the elastomer is a combination of a
natural rubber and a styrene/isoprene block copolymer.
8. The assembly of claim 7, wherein the weight ratio of tackifier to
elastomer is greater than 0.8:1.
9. The assembly of claim 8, wherein the tackifier is a rosin ester.
10. A kit for dispensing a series of adhesive sheets from a continuous
carrier of flexible sheet material in roll form comprising the adhesive
sheet assembly of claim 1 and a dispenser adapted for holding the adhesive
sheet assembly, allowing the adhesive sheet assembly to rotate about the
axis of the roll form, and serially presenting each adhesive sheet for
removal by pulling on the first portion of each adhesive sheet.
11. The kit of claim 10, wherein the dispenser is a container adapted for
substantially enclosing the adhesive sheet assembly, the dispenser having
a top and a bottom and an opening at or near the top for dispensing the
first end of the continuous carrier.
12. A process for making the adhesive sheet assembly of claim 1 comprising:
A. Adhering a continuous carrier having a back side and a front and two
substantially parallel side edges extending in a longitudinal direction to
the back side of a continuous flexible polymer film, polymer-reinforced
sheet or cloth having a Taber stiffness of not less than 0.03 measured
according to ASTM D747 A and having two substantially parallel side edges
extending in a longitudinal direction, a front side facing away from the
carrier capable of receiving markings, a back side facing toward the back
side of the carrier substantially covered with a pressure sensitive
adhesive such that the carrier substantially covers the pressure-sensitive
adhesive to form a continuous web having a front side capable of receiving
markings, wherein the continuous carrier is located on the back side of
the continuous flexible polymer film, polymer-reinforced sheet or cloth,
and two substantially parallel side edges extending in a longitudinal
direction of the web;
B. Scoring the front side of the continuous flexible polymer film,
polymer-reinforced sheet or cloth to serially cut out longitudinally
spaced apart adhesive sheets adhered to the carrier; and
C. Scoring the front side of the carrier to cut out a cover piece from the
carrier adhered to each of the adhesive sheets and having an outer
peripheral edge which has at least 40 percent of its total length in
registration with the scoring of step B,
wherein the pressure sensitive adhesive has an initial tack value of at
least 200 g measured according to ASTM D2979 on a Polyken.TM. probe tack
tester, an adhesive tack sufficient to prevent conformability failure of
the adhesive sheet after 10 hours conformability testing, and an adhesive
strength of at least 100 N/m according to ASTM D1000 and each adhesive
sheet is capable of being removed from a substrate to which it is adhered
without leaving a substantial amount of residue on the substrate; and
wherein the adhesive sheets are not scored parallel to the outer peripheral
edge of the cover piece adhered to each adhesive sheet.
13. The process of claim 12, wherein the scoring of step C not in
substantial registration with the scoring of step B is carried out before
carrying out the scoring in substantial registration with the scoring of
step B.
14. The process of claim 13, wherein the scoring of step B in substantial
registration with the scoring of step C is carried out after the scoring
of step C not in substantial registration with the scoring of step B and
together with the scoring in step C in substantial registration with the
scoring of step B.
15. A process for making the adhesive sheet assembly of claim 1 comprising:
A. Adhering a continuous carrier having a back side and a front side and
two substantially parallel side edges extending in a longitudinal
direction to the back side of a continuous flexible polymer film,
polymer-reinforced sheet or cloth having a Taber stiffness of not less
than 0.03 measured according to ASTM D747 A and having two substantially
parallel side edges extending in a longitudinal direction, a front side
facing away from the carrier capable of receiving markings, a back side
facing toward the back side of the carrier substantially covered with a
pressure sensitive adhesive such that the carrier substantially covers the
pressure-sensitive adhesive to form a continuous web having a front side
capable of receiving markings, wherein the continuous carrier is located
on the back side of the continuous flexible polymer film,
polymer-reinforced sheet or cloth, and two substantially parallel side
edges extending in a longitudinal direction of the web;
B. Scoring the front side of the continuous flexible polymer film,
polymer-reinforced sheet or cloth to serially cut out longitudially spaced
apart adhesive sheets adhered to the carrier; and
C. Scoring the front side of the carrier to cut out a cover piece from the
carrier adhered to each of the adhesive sheets and having an outer
peripheral edge which has at least 40 percent of its total length in
registration with the scoring of step B,
wherein the pressure sensitive adhesive has an initial tack value of at
least 200 g measured according to ASTM D2979 on a Polyken.TM. probe tack
tester, an adhesive tack sufficient to prevent conformability failure of
the adhesive sheet after 10 hours conformability testing, and an adhesive
strength of at least 100 N/m according to ASTM D1000 and each adhesive
sheet is capable of being removed from a substrate to which it is adhered
without leaving a substantial amount of residue on the substrate; and
wherein step B and step C are carried out on both sides of the web
simultaneously.
16. The process of claim 15, wherein the scoring of steps B and C is
carried out continuously on both sides of the web at substantially the
same location by feeding the web between a first rotary die and a second
rotary die, such that the first rotary die is positioned over the front
side of the web and second rotary die is positioned over the back side of
the web, the first rotary die adapted to cut the score lines of step B and
second rotary die adapted for cutting the score lines of steps C.
17. The process of claim 12, wherein the web formed in step A is cut to
form a plurality of webs, each having two substantially parallel side
edges extending in a longitudinal direction of the web from the first end
to the second end.
18. A process for making printed adhesive sheets on demand comprising:
A. Feeding the adhesive sheet assembly of claim 1 into a printer adapted
for receiving the adhesive sheet assembly and for receiving signals from a
computer and
B. Sending electronic signals to the printer from the computer directing
the printer to print a selected insignia on a specified number of adhesive
sheets in the adhesive sheet assembly.
19. An adhesive sheet assembly comprising:
a continuous carrier of flexible sheet material in roll form, the carrier
having two substantially parallel side edges extending in a longitudinal
direction of the carrier;
a series of longitudinally spaced adhesive sheets on the carrier, each
adhesive sheet having a front side facing away from the carrier capable of
receiving markings, a back side facing toward the carrier substantially
covered with a pressure sensitive adhesive, the back side having a first
portion and a second portion;
a continuous cut in the carrier defining, for each adhesive sheet, one
cover piece cut from the web such that the cover piece has an outer
peripheral edge within the first portion on the backside of the adhesive
sheet, so that the cover piece may be separated from the carrier and
retained on the first portion of the backside of the adhesive sheet
without extending beyond the outer peripheral edge of the adhesive sheet
when the adhesive sheet is peeled off the carrier due to adhesion between
the cover piece and the adhesive sheet,
wherein
at least 40 percent of the total length of the outer peripheral edge of
each cover piece is substantially in registration with the outer
peripheral edge of the adhesive sheet to which it is adhered;
the continuous cut does not extend through the substantially parallel side
edges of the continuous carrier; and
each longitudinally spaced adhesive sheet on the carrier is not perforated
or cut parallel to the outer peripheral edge of the cover piece adhered to
that adhesive sheet; or
each adhesive sheet comprises a flexible polymer film, polymer-reinforced
sheet or cloth; and
each adhesive sheet is capable of being removed from a substrate to which
it is adhered without leaving a substantial amount of residue on the
substrate.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is in the field of adhesive sheets in roll form and
processes for making them.
2. Description of Related Art
Label assemblies in which a release agent coated carrier sheet has a
plurality of pressure sensitive adhesive coated labels adhered to it are
known. Such label assemblies are available in sheet or roll form with, or
without, a blank facing capable of receiving markings. Such label
assemblies are often used to mark folders, address envelopes, label
containers, label file cabinets, label shelves and so forth. Typically,
such labels are made of paper and are removed from the carrier sheet by
bending the carrier sheet and "picking" at the label.
Those known label assemblies are often unsatisfactory for use in an
industrial setting. Paper is adversely affected by solvents, oils and
humidity, resulting in staining and curling, is easily torn and damaged
and often has insufficient conformability to nonflat surfaces. The
adhesive used is generally either ineffective to hold the label on a
nonsmooth or contaminated surface, or leaves an adhesive residue on the
surface after it is removed, which interferes with use as a temporary or
repositionable label.
Although paper labels coated within a low-tack repositionable
pressure-sensitive adhesive have been a phenomenal success in the office
setting in which the note is typically applied to a paper surface, the
inventors have found that such notes perform poorly on substrates which
have an irregular surface and/or have a surface with low surface energy or
contamination which reduces the effectiveness of the adhesive. Such
surfaces are prevalent in industrial settings, research and development
laboratories, the construction industry, warehouses, and other settings
which require the ability to post temporary notes on non-paper surfaces.
Such settings also require that the labels be dispensed in a manner that
facilitates removal from carrier and application to the substrate. Workers
and technicians often are required to wear gloves, they often are in
situations in which they have only one hand available for removing and
applying the note and they are often pressed for time. The typical
assemblies used to dispense self-adhesive labels are not satisfactory for
meeting these end use requirements.
SUMMARY OF THE INVENTION
The problem of providing robust markable removable printable adhesive
sheets in a form that can be easily applied in an industrial environment
is solved by the present invention.
One aspect of this invention are adhesive sheet assemblies comprising:
a continuous carrier of flexible sheet material in roll form, the carrier
having two substantially parallel side edges extending in a longitudinal
direction of the carrier;
a series of longitudinally spaced adhesive sheets on the carrier, each
adhesive sheet having a front side facing away from the carrier capable of
receiving markings, a back side facing toward the carrier substantially
covered with a pressure sensitive adhesive, the back side having a first
portion and a second portion;
at least one cut in the carrier defining, for each adhesive sheet, one
cover piece cut from the web such that the cover piece has an outer
peripheral edge within the first portion on the backside of the adhesive
sheet, so that the cover piece may be separated from the web and retained
on the first portion of the backside of the adhesive sheet when the
adhesive sheet is peeled off the carrier due to adhesion between the cover
piece and the adhesive sheet.
Another aspect of this invention is a process for making the adhesive sheet
assemblies of the present invention comprising:
A. Adhering a continuous carrier having two substantially parallel side
edges extending in a longitudinal direction to the back side of a
continuous flexible polymer film, polymer-reinforced sheet or cloth having
a Taber stiffness of not less than 0.03 measured according to ASTM D747 A
and having two substantially parallel side edges extending in a
longitudinal direction, a front side facing away from the carrier capable
of receiving markings, a back side facing toward the carrier substantially
covered with a pressure sensitive adhesive such that the carrier
substantially covers the pressure-sensitive adhesive to form a continuous
web having a front side capable of receiving markings, a continuous
carrier on the back side, and two substantially parallel side edges
extending in a longitudinal direction of the web;
B. Scoring the front side of the web to serially cut out spaced apart
adhesive sheets adhered to the carrier; and
C. Scoring the back side of the web to cut out a cover piece from the web
having an outer peripheral edge which has at least 40, preferably at least
50, more preferably at least 60, percent of its total length in
registration with the scoring of step B.
These and other aspects of the invention are described in greater detail
below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a kit for dispensing adhesive sheets according to the present
invention comprising the adhesive sheet assembly 1 according to the
present invention in roll form and a dispenser 2.
FIG. 2 shows an enlarged portion of the unrolled end of the adhesive sheet
assembly 1 shown in FIG. 1 as an adhesive sheet 4 is removed.
FIG. 3 shows the front side of an enlarged portion of the unrolled end of
the adhesive sheet assembly 1 shown in FIG. 1.
FIG. 4 shows the back side of the enlarged portion of the unrolled end of
the adhesive sheet assembly 1 shown in FIG. 3.
FIG. 5 shows an enlarged cross sectional view of the indicated portion of
FIG. 3.
FIG. 6 shows an alternative embodiment of the front side of an enlarged
portion of the unrolled end of the adhesive sheet assembly 1 which has
perforations 11 between each adhesive sheet 4.
FIG. 7 shows another alternative embodiment of the front side of an
enlarged portion of the unrolled end of the adhesive sheet assembly 1 in
which each adhesive sheet 4 has a triangular cover piece 5 in hidden view
behind each adhesive sheet.
FIG. 8 shows the back side of the enlarged portion of the unrolled end of
the adhesive sheet assembly 1 shown in FIG. 7 in which each triangular
cover piece 5 is in exposed view.
FIG. 9 shows another alternative embodiment of the front side of an
enlarged portion of the unrolled end of the adhesive sheet assembly 1 in
which each adhesive sheet 4 has a truncated triangular (i.e., rhomboid)
cover piece 5 in hidden view behind each adhesive sheet.
FIG. 10 shows the back side of the enlarged portion of the unrolled end of
the adhesive sheet assembly 1 shown in FIG. 9 in which each truncated
triangular cover piece 5 is in exposed view.
FIG. 11 shows another alternative embodiment of the front side of an
enlarged portion of the unrolled end of the adhesive sheet assembly 1 in
which each adhesive sheet 4 has a smaller triangular cover piece 5 in
hidden view behind each adhesive sheet.
FIG. 12 shows the back side of the enlarged portion of the unrolled end of
the adhesive sheet assembly 1 shown in FIG. 11 in which each smaller
triangular cover piece 5 is in exposed view.
FIG. 13 shows yet another alternative embodiment of the front side of an
enlarged portion of the unrolled end of an adhesive sheet assembly in
which each adhesive sheet 4 is cut in a nonrectangular shape, in this
illustration an apple and a bunch of grapes, respectively, in which cover
piece 5 is in hidden view behind each adhesive sheet.
FIG. 14 shows the back side of the enlarged portion of the unrolled end of
the adhesive sheet assembly shown in FIG. 13 in which each cover piece 5
is in exposed view.
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment, at least 40, preferably at least 50, and even
more preferably at least 60, percent of the total length of the outer
peripheral edge of each cover piece is substantially in registration with
the outer peripheral edge of the adhesive sheet to which it is adhered. As
used herein, the term "substantially in registration" means that the outer
peripheral edge or score line of the cover piece follows, and is lined up
with, the configuration of the outer peripheral edge of the adhesive sheet
so that their respective edges are within a short distance, preferably
within 1 mm, from one another over the specified length.
In the same or another preferred embodiment, the at least one cut does not
extend through the substantially parallel side edges of the continuous
carrier.
In the same or another embodiment, each longitudinally spaced adhesive
sheet on the web is preferably not perforated parallel to, and within a
few millimeters of, the outer peripheral edge of the cover piece adhered
to that adhesive sheet.
Preferably, each adhesive sheet comprises a flexible polymer film,
polymer-reinforced sheet or cloth having a Taber stiffness of not less
than 0.03 measured according to ASTM D747 A. The pressure sensitive
adhesive also preferably has an initial tack value of at least 200 g
measured according to ASTM D2979 on a Polyken.TM. probe tack tester, an
adhesive tack sufficient to prevent conformability failure of the adhesive
sheet after 10 hours conformability testing, and an adhesive strength of
at least 100 N/m according to ASTM D1000. Each adhesive sheet is
preferably capable of being removed from a substrate to which it is
adhered without leaving an adhesive residue on the substrate.
The carrier may be any material that has less adhesion to the adhesive than
the adhesive substrate and has sufficient strength to resist tearing as it
is removed from the adhesive. The release property of the carrier may be
inherent in the material of the carrier or may be due to the presence of a
release agent on the surface of the carrier, or both. Materials having an
inherent release property include those made of a synthetic nonpolar
material, such as homopolymers derived from unsaturated olefins, e.g.,
polyethylene, polypropylene, etc., and release agents include, for
example, silicone-containing agents. The release sheet preferably has a
Taber stiffness measured according to ASTM D747 greater than that of the
adhesive sheet.
The adhesive sheets are preferably made of a flexible polymer film,
polymer-reinforced sheet or cloth having a Taber stiffness of not less
than 0.03, preferably not less than 0.05, measured according to ASTM D747.
The polymer film, polymer-reinforced sheet or cloth preferably has a
tensile strength of at least 2000, preferably 4000 and more preferably
5000, N/m, up to any value, such as up to 8000 N/m and it also preferably
has a minimum elongation of at least about 4 percent and more preferably
at least about 50 percent, the tensile strength and percent minimum
elongation being measured according to ASTM D1000.
The film, sheet or cloth may be selected from a wide range of materials.
Examples include polymer films made of natural and/or synthetic polar
and/or nonpolar materials such as polyolefins, e.g., homopolymers and
interpolymers derived from substituted and unsubstituted olefinically
unsaturated hydrocarbons including ethylene, propylene, styrene,
butadiene, dicyclopentadiene, etc., and materials which contain polar
functional groups such as hydroxys, etherals, carbonyls, carboxylic acids
(including salts thereof), carboxylic acid esters (including thio esters),
carboxylic anhydrides, amides, amines, etc. Synthetic materials having
polar groups are preferred. Illustrative examples include polyesters,
polyamides, and carboxylated styrene-butadiene polymers.
The polymer-reinforced sheets comprise at least one of the natural or
synthetic polymers described above together with a reinforcing material.
The reinforcing material may be organic or inorganic. Illustrative organic
materials include natural materials such as cellulosic fibers such as
cotton, paper, hemp, etc., and synthetic materials such as fibers made of
the aforementioned natural or synthetic polymers. Inorganic materials
include any of the many well known fillers used in the plastics industry
such as silica, talc, mica, etc.
The cloth is one that is woven from natural or synthetic fibers. The
natural fibers are preferably cotton and the synthetic fibers are
preferably polar interpolymers derived from olefinically unsaturated
hydrocarbons.
The front surface of the film, sheet or cloth is capable of receiving
markings. This capability is either an inherent property of the film,
sheet or cloth or is obtained by a treatment of its surface using
conventional means known in the art. Preferably the front surface is
capable of receiving markings with a ballpoint pen, a marking pen or a
pencil. It is also preferable that the front surface be capable of
absorbing ink such as ballpoint or marking pen ink into the surface to
reduce potential smearing of the ink after it is applied.
The adhesive may be applied to the above films, sheets and cloths in a
conventional manner, such as by spraying, knife coating, roller coating,
casting, drum coating, extrusion coating, coextrusion coating, and the
like or unsupported pressure sensitive adhesive may be transferred or
laminated to the film, sheet or cloth. The adhesive is preferably coated
in a manner which covers substantially the entire back side of the film,
sheet or cloth. The adhesive is preferably coated at a thickness in the
range from 0.5 to 3 mil, more preferably in the range from 1 to 3 mil.
The adhesive combines an initial tack value of at least 200 g according to
ASTM D2979 measured on a Polyken.TM. probe tack tester, an adhesive
strength of at least 100 N/m according to ASTM D1000 and an adhesive tack
sufficient to prevent conformability failure of the adhesive sheet after
10 hours conformability testing (which is further described below) and yet
having a cohesive strength sufficient to allow removal of the adhesive
sheet from the substrate without leaving any residue behind on the
substrate.
Typically, the adhesives which are useful in the present invention comprise
an elastomeric polymer. Examples of useful elastomeric polymers include
natural rubber, styrene/diene rubber such as styrene/butadiene block
copolymer, styrene/isoprene block copolymer, styrene/ethylene-butylene
block copolymer, polyisobutylene rubber, and acrylic elastomer. Specific
examples of elastomeric polymers include Heveacrumb.TM. (natural rubber)
available from Herron & Meyer, Synpol.TM. (a styrene/butadiene copolymer
rubber) available from Ameripol Synpol Corp., Vistanex.TM. (a
polyisobutylene elastomer) available from Exxon Chemical, Duro-Tak.TM. (an
acrylic resin elastomeric adhesive) available from National Starch and
Chemical Corp., and Aroset.TM. (a modified acrylic resin elastomeric
adhesive) available from Ashland Chemical, Inc.
The adhesives useful in the present invention also may contain one or more
tackifier resins such as rosin, hydrogenated rosin, rosin ester, synthetic
hydrocarbon tackifier, and low molecular weight, low glass transition
temperature polycarboxylic acid esters. Preferred tackifiers include rosin
esters, polyterpenes, and polybutenes. Specific examples of tackifier
resins include Foral.TM. (a rosin ester tackifier) and Piccolyte.TM. (a
polyterpene tackifier), both available from Hercules, Inc., and
Indopol.TM. (a polybutene tackifier) available from Amoco Chemicals Corp.
Antioxidants are employed to the extent necessary to prevent degradation of
the adhesive with time. Examples include hydroquinone and hindered phenol
antioxidants. Specific examples of antioxidants include Santovar A
(2,5-di-tert-amylhydroquinone antioxidant) available from Flexsys America
L.P., Agerite Resin D (polymerized 1,2-dihydro-2,2,4-trimethylquinoline
monomer) available from R. T. Vanderbilt Co. and Wingstay L (butylated
reaction product of p-cresol and dicyclopentadiene) available from
Goodyear Tire & Rubber Co.
Adhesive formulations may include a plasticizer, such as a polyketone
resin, and/or a surfactant, such as Tween.TM., a polysorbate 20 surfactant
available from ICI Specialties Mfg.
When the adhesive contains a tackifier, the tackifier may be present in a
wide range of amounts, depending on the amount required to achieve the
required initial tack value, adhesive tack and adhesive strength. In one
embodiment, the adhesive has a weight ratio of tackifier to elastomer in
the range from 0.5 to 2.0:1, preferably in the range from 0.8 to 1.8:1.
The adhesive has an initial tack value of at least 200 g, preferably at
least 300 g, measured according to ASTM D2979 on a Polyken.TM. probe tack
tester, an adhesive tack sufficient to prevent conformability failure of
the adhesive sheet after 10 hours, preferably after 24 hours,
conformability testing (described below), and an adhesive strength of at
least 100 N/m, preferably at least 200 N/m, according to ASTM D1000.
The adhesive preferably has a high cohesive strength to prevent adhesive
residue from remaining on the substrate when the adhesive sheet is
removed. One method for determining cohesive strength is to conduct a
shear strength test according to ASTM D3654-88, PSTC-7 (PSTC refers to the
Pressure Sensitive Tape Council) to determine whether the adhesive
undergoes cohesive failure at the conclusion of that test. This test is
further described below.
For applying the adhesive to an adhesive sheet, appropriate types and
amounts of curing agent, accelerator and solvent are typically included in
the adhesive formulation. Examples of curing agents include zinc oxide,
such as ASARCO available from Jenson-Sauders Associates, Inc., and
melamine resin such as Uformite.TM. available from Reichhold Chemical
Coating Division. Examples of accelerators include zinc dithiocarbamates
such as Methyl Zimate.TM. (zinc dimethyldithiocarbamate) and thiuram
sulfides such as Sulfads.TM. (dipentamethylene thiuram hexasulfide), both
available from R.T. Vanderbilt Co. Examples of useful solvents include
toluene, heptane, xylene, methyl ethyl ketone, isopropyl alcohol and ethyl
acetate.
In one preferred embodiment of this invention, the adhesive formulation
used to make the adhesive sheets comprises at least one elastomer, at
least one tackifier, at least one antioxidant, at least one curing agent,
at least one accelerator, and at least one solvent. The elastomer is
preferably present in an amount of at least 5 wt %, more preferably at
least 10 wt %, up to 25 wt %, more preferably up to 20 wt %. The tackifier
is preferably present in an amount of at least 5 wt %, more preferably at
least 10 wt %, up to 40 wt %, more preferably up to 30 wt %. The curing
agent is preferably present in an amount of at least 0.1 wt % up to 10 wt
%. The accelerator is preferably present in an amount from 0.1 to 1 wt %.
In another preferred embodiment of this invention, the adhesive formulation
used to make the adhesive sheets comprises at least one acrylic-based
adhesive in an appropriate solvent.
One approach to preparing an adhesive for use in this invention is to add
elastomeric polymer, antioxidant, curing agent and accelerator to a
tackifier resin which has been thinned with an appropriate solvent, adding
additional appropriate solvent as needed.
Curing of the adhesive may be activated by any conventional method, such as
by exposure to air, elevated temperatures and/or radiation. Examples of
radiation include ultraviolet light and actinic radiation. Curing via
exposure to radiation includes the use of curing initiators which generate
sufficient free radicals upon exposure to the selected radiation to
initiate curing of the adhesive. Such initiators are well known in the
polymer curing art.
In yet another preferred embodiment of this invention, the adhesive is
formulated with little or no solvent for application as a hot melt
thermoplastic adhesive. Hot melt thermoplastic adhesives typically contain
little or no solvent. Any of a wide range of thermoplastic adhesives may
be used as long as they comply with the conditions set forth above. They
are commercially available from several manufacturers. Examples include
HL-2194-X, HM-2703, HL-2198-X and HL-2268-X available from H. B. Fuller
Co.; Duro-Tak.TM. 9820, 6123, 4136 and 1236 available from National Starch
and Chemical Corp.; CA-501 (SIS/SBS), CA-502-4A (SIS/SBS), CA-503-A
(SIS/SBS), CA-506 (SIS/SBS), C-X805-1 (Acrylic), C-882 (Acrylic), and
C-X885 (Acrylic) available from Century International and H2091, H2114-01,
and 801-375 available from Findley Adhesives, Inc. Suitable hot melt
thermoplastic adhesives are also disclosed, for example, in U.S. Pat. No.
4,728,572, which is incorporated herein by reference.
FIGS. 1-7 show examples of embodiments of the invention and components for
making those embodiments.
FIG. 1 shows a kit for dispensing adhesive sheets according to the present
invention comprising the adhesive sheet assembly 1 according to the
present invention in roll form 1A and a dispenser 2. The adhesive sheet
assembly 1, shown in hidden view within dispenser 2, is comprised of a
carrier 3 with a series of adhesive sheets 4 on one face of carrier 3.
Each adhesive sheet 4 has a cover piece 5 for peeling adhesive sheet 4
from carrier 3. Dispenser 2 has a passageway 6 for withdrawing additional
lengths of adhesive sheet assembly 1 from the roll 1A within dispenser 2.
FIG. 2 shows an enlarged portion of the unrolled end of the adhesive sheet
assembly 1 shown in FIG. 1 as one adhesive sheet 4 is being removed and
another adhesive sheet 4 prior to initiation of removal. The cut out
peripheral edge 7 in carrier 3 corresponds in size, shape and position to
the outer peripheral edge 5A of cover piece 5. Hidden transverse score
line 8 corresponds to the portion of the length of cut out peripheral edge
7A that is not substantially in registration with the outer peripheral
edge 4A of adhesive sheet 4. Transverse score line 8 divides adhesive
sheet 4 into a first portion 8A and a second portion 8B. Cut out
peripheral edges 7B and 7C correspond to the portions of the length of cut
out peripheral edge 7 that are substantially in registration with the
outer peripheral edge 4A of adhesive sheet 4. Cut out peripheral edge 7
does not intersect the two substantially parallel outer side edges 3A of
carrier 3. Adhesive sheet 4 may optionally have printed on it insignia 9.
FIGS. 3 and 4 show the front and back sides, respectively, of an enlarged
portion of the unrolled end of the adhesive sheet assembly 1 shown in FIG.
1. These figures in particular show the correspondence between the outer
peripheral edge 4A of adhesive sheet 4 and the outer peripheral edge 5A of
cover piece 5 and their relationship to the first portion 8A and second
portion 8B of adhesive sheet 4.
FIG. 5 shows an enlarged cross sectional view of the indicated portion of
FIG. 3. Adhesive sheet 4 is adhered to carrier 3 with adhesive 10.
Adhesive sheet 4, carrier 3, and adhesive 10 are selected so that adhesive
10 has a stronger adhesive bond to adhesive sheet 4 than to carrier 3.
FIG. 6 shows an alternative embodiment of the front side of an enlarged
portion of the unrolled end of the adhesive sheet assembly 1 which has
perforations 11 between each adhesive sheet 4 to aid in separating one or
more adhesive sheets 4 from the adhesive sheet assembly 1 prior to
separating each adhesive sheet 4 from carrier 3.
FIGS. 7 and 8 show the front and back sides, respectively, of another
alternative embodiment of an enlarged portion of the unrolled end of the
adhesive sheet assembly 1 in which each adhesive sheet 4 has a triangular
cover piece 5 shown in hidden view in FIG. 7 and in exposed view in FIG.
8. Transverse score line 8 divides adhesive sheet 4 into a first portion
8A and a second portion 8B. Cut out peripheral edges 7B and 7C correspond
to the portions of the length of cut out peripheral edge 7 that are
substantially in registration with the outer peripheral edge 4A of
adhesive sheet 4. Cut out peripheral edge 7 does not intersect the two
substantially parallel outer side edges 3A of carrier 3.
FIGS. 9 and 10 show the front and back sides, respectively, of another
alternative embodiment of an enlarged portion of the unrolled end of the
adhesive sheet assembly 1 in which each adhesive sheet 4 has a truncated
triangular cover piece 5 shown in hidden view in FIG. 9 and in exposed
view in FIG. 10. Transverse score line 8 divides adhesive sheet 4 into a
first portion 8A and a second portion 8B. Cut out peripheral edges 7B and
7C correspond to the portions of the length of cut out peripheral edge 7
that are substantially in registration with the outer peripheral edge 4A
of adhesive sheet 4. Cut out peripheral edge 7 does not intersect the two
substantially parallel outer side edges 3A of carrier 3.
FIGS. 11 and 12 show the front and back sides, respectively, of another
alternative embodiment of an enlarged portion of the unrolled end of the
adhesive sheet assembly 1 in which each adhesive sheet 4 has a smaller
triangular cover piece 5 shown in hidden view in FIG. 11 and in exposed
view in FIG. 12. Transverse score line 8 divides adhesive sheet 4 into a
first portion 8A and a second portion 8B. Cut out peripheral edges 7B and
7C correspond to the portions of the length of cut out peripheral edge 7
that are substantially in registration with the outer peripheral edge 4A
of adhesive sheet 4. Cut out peripheral edge 7 does not intersect the two
substantially parallel outer side edges 3A of carrier 3.
FIGS. 13 and 14 show yet another alternative embodiment of the front side
of an enlarged portion of the unrolled end of an adhesive sheet assembly
in which each adhesive sheet 4 is cut in a nonrectangular shape, in this
illustration an apple and a bunch of grapes, respectively, in which cover
piece 5 is in hidden view in FIG. 13 and in exposed view in FIG. 14.
Transverse score line 8 divides adhesive sheet 4 into a first portion 8A
and a second portion 8B. Cut out peripheral edge 7B corresponds to the
portions of the length of cut out peripheral edge 7 that are substantially
in registration with the outer peripheral edge 4A of adhesive sheet 4. Cut
out peripheral edge 7 does not intersect the two substantially parallel
outer side edges 3A of carrier 3.
FIGS. 13 and 14 illustrate that the adhesive sheets and their corresponding
cover pieces can be cut to any shape, such as animals, plants, fruit,
symbols, etc., which can be of particular utility in applications
involving children, including, for example, games and learning aids,
especially in view of the effective, but nonpermanent, adhesiveness of the
adhesive sheets of this invention.
Adhesives that may be used as the adhesive sheet adhesive in the present
invention are illustrated by the examples which follow. These examples are
not to be construed as limiting the scope of the invention, which is
defined by the appended claims.
TEST METHODS
Test for Conformability
A sample of the rectangular adhesive sheet measuring 0.5 inch by 1.5 inch
is applied to a clean, polished half-inch diameter stainless steel
cylinder such that the short side is oriented along the axis of the
cylinder and the long side is oriented along the circumference of the
cylinder, known as "flagging". The cylinder is then exposed to a
temperature of 77.degree..+-..degree.5 F. and a relative humidity not
greater than 80% for a period of 10 hours.
Conformability failure is indicated by opening up of the flags, i.e.,
visible edge separation, at the conclusion of the 10 hour test. It is a
pass/fail test.
Test for Cohesive Strength
Cohesive strength may be determined indirectly by measuring the shear
strength of the adhesive according to ASTM D3654-88, also known as PSTC-7,
and recording whether adhesive is left on both the adhesive sheet and the
panel to which it was adhered after failure. In this case, PSTC-7 has been
modified to use 1.times.0.5 inch samples. A sample of the rectangular
adhesive sheet measuring 1.times.0.5 inch is applied to a vertical
stainless steel panel with a 0.5 inch overlap joint. A mass of 1000 g is
suspended from the sample and the time until failure is measured in an
environment having a temperature of 23.degree. C. and a relative humidity
of 50 percent. A determination is then made whether adhesive is left on
both the tape and the panel by visual inspection. If there is, the test
shows cohesive failure.
If there is no adhesive left on the panel, the test indicates adhesive
failure to the panel, i.e., the cohesive strength is greater the shear
strength of the bond to the panel, and the adhesive passes the test for
cohesive strength.
If there is some or no adhesive left on the adhesive sheet and it has been
transferred to the panel, the test does not provide information about the
cohesive strength of the adhesive, but rather shows failure of the
adhesive to form a sufficient adhesive bond to the backing material of the
adhesive sheet. This indicates the need for either another adhesive,
another backing material, or the need to pre-treat the surface of the
backing material to be coated with adhesive such that it forms a stronger
bond with the adhesive, such as with a sizing agent.
EXAMPLES
The following are examples of formulations of adhesives which are useful
for making the adhesive sheet assemblies according to the present
invention. These formulations may be coated or transferred onto any of the
films, sheets or cloths described above as useful for making the adhesive
sheets.
TABLE I
COMPOSITION OF FORMULATIONS A, B AND C
IN WEIGHT-PERCENT
INGREDIENT A B C
Heveacrumb .TM. SMR-5LX Lamco.sup.1 3.86 -- 10.18
Synpol .TM. Type 1011A.sup.2 11.58 17.02 --
Vistanex MM-L-80.sup.3 -- -- 2.60
Foral .TM. 105.sup.4 18.52 15.32 --
Piccolyte S-115.sup.5 -- -- 14.73
Herolyn Dphu 6 -- -- 3.12
Indopol H-100.sup.7 -- -- 3.12
Santovar .TM. A.sup.8 0.15 0.09 --
Agarite .TM. Resin D.sup.9 0.08 0.09 --
Wingstay .TM. L Powder.sup.10 -- -- 0.14
ASARCO .TM. ZO-77T.sup.11 7.72 8.51 0.64
Methyl Zimate.sup.12 0.62 0.68 0.50
Sulfads .TM. Powder.sup.13 0.04 0.04 --
Tween .TM. 20.sup.14 -- -- 0.12
K-1717B.sup.15 -- -- 1.22
Solvent balance balance balance
.sup.1 Natural rubber elastomer available from Herron & Meyer
.sup.2 Styrene butadiene copolymer elastomer available from American Synpol
Corp.
.sup.3 Polyisobutylene elastomer available from Exxon Chemical
.sup.4 Rosin ester tackifier available from Hercules, Inc.
.sup.5 Polyterpener resin tackifier available from Hercules, Inc.
.sup.6 Hydrogenated methyl ester of rosin tackifier available from
Hercules, Inc.
.sup.7 Polybutene tackifier available from Amoco Chemical Corp.
.sup.8 2,5-di-tert-amylhydroquinone antioxidant available from Flexsys
America L.P.
.sup.9 Antioxidant available from R.T. Vanderbilt Co.
.sup.10 Antioxidant available from Goodyear Tire & Rubber Co.
.sup.11 Zinc oxide curing agent available from Jenson-Souders Assocs., Inc.
.sup.12 Zinc dimethyldithiocarbamate accelerator available from R.T.
Vanderbilt Co.
.sup.13 Dipentatnethylene thiuram hexasulfide accelerator available from
R.T. Vanderbilt Co.
.sup.14 Polysorbate 20 surfactant available from ICI Specialties Mfg.
.sup.15 Polyketone resin plasticizer available from Lawter Chemical, Inc.
Formulation D
An acrylic-based adhesive formulation D is prepared by combining 99.72 wt %
Duro-Tak.TM. 80-1047 (an acrylic resin available from National Starch and
Chemical Co.) with 0.17 wt % Uformite-27-803 (a melamine resin curing
agent available from Reichhold Chemical Coating Div.) in an appropriate
solvent (balance).
Formulation E
Another acrylic-based adhesive formulation is prepared by diluting
Aroset.TM. 1044-Z-40 (an acrylic resin adhesive available from Ashland
Chemical, Inc.) with an appropriate solvent so that the resin comprises
39-41 wt % of the formulation.
Formulation F
Yet another acrylic-based adhesive formulation F is prepared by diluting
Aroset.TM. 1085-Z-38 (an acrylic resin adhesive also available from
Ashland Chemical) with an appropriate solvent so that the resin comprises
36.5-38.5 wt % of the formulation.
Another aspect of this invention is a process for making the adhesive sheet
assembly of the present invention comprising:
A. Adhering a continuous carrier having two substantially parallel side
edges extending in a longitudinal direction to the back side of a
continuous flexible polymer film, polymer-reinforced sheet or cloth having
a Taber stiffness of not less than 0.03 measured according to ASTM D747 A
and having two substantially parallel side edges extending in a
longitudinal direction, a front side facing away from the carrier capable
of receiving markings, a back side facing toward the carrier substantially
covered with a pressure sensitive adhesive such that the carrier
substantially covers the pressure-sensitive adhesive to form a continuous
web having a front side capable of receiving markings, a continuous
carrier on the back side, and two substantially parallel side edges
extending in a longitudinal direction of the web;
B. Scoring the front side of the web to serially cut out spaced apart
adhesive sheets adhered to the carrier; and
C. Scoring the back side of the web to cut out a cover piece from the web
having an outer peripheral edge which has at least 40 percent of its total
length in registration with the scoring of step B,
wherein the pressure sensitive adhesive has an initial tack value of at
least 200 g measured according to ASTM D2979 on a Polyken.TM. probe tack
tester, an adhesive tack sufficient to prevent conformability failure of
the adhesive sheet after 10 hours conformability testing, and an adhesive
strength of at least 100 N/m according to ASTM D1000 and each adhesive
sheet is capable of being removed from a substrate to which it is adhered
without leaving an adhesive residue on the substrate.
In one embodiment of the process of this invention, the scoring of step C
not in substantial registration with the scoring of step B is preferably
carried out before carrying out the scoring in substantial registration
with the scoring of step B. The scoring of step B in substantial
registration with the scoring of step C may also be carried out after the
scoring of step C not in substantial registration with the scoring of step
B and together with the scoring in step C in substantial registration with
the scoring of step B.
Steps B and C are preferably carried out on both sides of the web
simultaneously, such as by applying a first die adapted to cut the
required score lines on the front side of the web to the first side of the
web and, at the same time, applying a second die adapted to cut the
required score lines on the back side of the web to the back side of the
web. The first and second dies may be positioned across the web from each
other or offset.
The scoring of steps B and C may be carried out continuously on both sides
of the web at substantially the same location by feeding the web between a
first rotary die and a second rotary die, such that the first rotary die
is positioned over the front side of the web and second rotary die is
positioned over the back side of the web, the first rotary die adapted to
cut the score lines of step B and second rotary die adapted for cutting
the score lines of steps C.
The web formed in step A may be cut to form a plurality of webs, each
having two substantially parallel side edges extending in a longitudinal
direction of the web from the first end to the second end. The plurality
of webs may be processed through steps B and C simultaneously, if desired,
or the web formed in step A may be cut to form a plurality of webs as
above after conducting steps B and C, steps B and C being used to generate
a plurality of columns of adhesive sheets for separation into individual
adhesive sheet assemblies by cutting the web into a plurality of webs
corresponding in number to the number of columns of adhesive sheets.
The adhesive sheet assemblies described herein are useful for posting notes
in an industrial setting, including production plants, research and
development laboratories, construction sites, warehouses, and other
non-office environments. They are also useful in the office environment
for applications in which typical repositionable notes are not
sufficiently robust, such as for posting on shelving and office equipment.
The adhesive sheets may be blank or may be pre-printed with words, logos
or other insignia.
Printing insignia on the adhesive sheets may be carried out on an as needed
basis by feeding the adhesive sheet assembly into a thermal printer,
preferably so that the portion of the adhesive sheet without the cover
piece (illustrated by the second portion 8B of each adhesive sheet 4 in
the drawings) enters the printer before the portion of the adhesive sheet
with the cover piece adhered to it (illustrated by the first portion 8A of
each adhesive sheet 4 in the drawings). In that way, adhesive sheets with
insignia may be generated on demand, preferably with the aid of a
computer, for only the number of adhesive sheets needed, reducing waste
caused by overruns and reducing or eliminating the need for storage space
for different types of adhesive sheets.
In one embodiment, the process for making printed adhesive sheets on demand
comprises:
A. Feeding the adhesive sheet assembly of the present invention into a
printer adapted for receiving the adhesive sheet assembly and for
receiving signals from a computer and
B. Sending electronic signals to the printer from the computer directing
the printer to print a selected insignia on a specified number of adhesive
sheets in the adhesive sheet assembly.
Although the invention has been described in considerable detail through
the preceding specific embodiments, it is to be understood that these
embodiments are for purpose of illustration only. Many variations and
modifications can be made by one skilled in the art without departing from
the spirit and scope of the invention.
Top